RECEPTOR MEDIATED TRANSPORT OF GLYCOPROTEINS

受体介导的内吞作用是一种普遍现象， 与细胞器生物发生、激素和促分裂原生理学有关， 大分子进入细胞的运输。 肺泡巨噬细胞表达a 甘露糖特异性受体，介导胞内吞和包装 来自细胞外空间的糖缀合物（包括溶酶体酶） 巨噬细胞的溶酶体。 我开发了一种形式动力学 准确描述稳态摄取的机制， 这种受体和开发的技术，研究部分的 内吞过程。 使用这些方法，我们已经能够 为了表明内体酸化在稳态期间是速率限制的， 摄取。 我建议研究内体酸化的机制， 完整细胞和分离的内体 受体与共价连接的荧光pH敏感发色团。 本文将介绍囊泡转运的细胞内途径和机制。 使用动力学和分馏技术进行研究。 标记配体和 标记受体（使用我开发的原位标记技术 将用于跟踪这些组分的进展 通过受体介导的内吞作用的细胞内途径。 的 内吞囊泡酸化在溶酶体释放中的作用 由酵母聚糖、内毒素和佛波醇肉豆蔻酸刺激的酶将 评估。 巨噬细胞溶酶体水解酶的刺激分泌 将被用作巨噬细胞在慢性炎症中作用的模型。 炎症 将研究分泌的机制， 甘露糖特异性内吞作用对胞外水解酶的调节 将在这些条件下确定。

Receptor mediated endocytosis is a general phenomena that has been found to be relevant to organelle biogenesis, hormone and mitogen physiology and the transport of macromolecules into cells. Alveolar macrophages express a mannose specific receptor that mediates the endodytosis and packaging of glycoconjugates (including lysosomal enzymes) from the extracellular space to the lysosomes of the macrophage. I have developed a formal kinetic mechanism which accurately describes the steady-state uptake mediated by this receptor and developed techniques for studying segments of the endocytic process in isolation. Using these approaches we have been able to show that endosome acidification is rate limiting during steady-state uptake. I proposed to study the mechanism of endosome acidification in intact cells and isolated endosomes using ligands specific for the mannose receptor with covalently attached fluorescent pH sensitive chromophores. The intracellular pathway and mechanism of vesicular transport will be studied using kinetic and fractionation techniques. Labelled ligand and labelled receptor (using a technique I have developed for in situ labelling of the receptor) will be used to follow the progression of these components through the intracellular pathway of receptor mediated endocytosis. The role of acidification of endocytic vesicles in the release of lysosomal enzymes stimulated by zymosan, endotoxin and phorbol myristic acid will be evaluated. The stimulated secretion of lysosomal hydrolases by macrophages will be used as a model for the role of macrophages in chronic inflammation. The mechanism of secretion will be studied and the role of mannose specific endocytosis in the regulation of extracellular hydrolase levels under these conditions will be determined.